320 CALIFORNIA ACADEMY OF SCIENCES. 



ceivable in grooves at their bases; all of about equal 

 length; the mental barbels disposed as two pairs situated 

 behind the rictus. 



Mouth terminal, the upper jaw very slightly project- 

 ing; a single series of somewhat compressed teeth in 

 each jaw and on the vomer; intermaxillaries each with 

 4 teeth; mandible with 8-12 teeth on each side; vomer 

 with about 8 on each half. 



Gill-openings very small, entirely below the first pec- 

 toral ray. Pectoral pore present; lateral line simple, 

 straight. 



Distance of first dorsal ray from tip of snout 3-| in the 

 length; the first dorsal ray scarcely higher than the sec- 

 ond, the last half as high as the second ray. 



Caudal narrow, emarginate, 5|--5f in the length. 



Anal rays gradually decreasing backward, their tips 

 projecting beyond the membrane. 



. Ventrals short, very narrow, the inner margins en- 

 tirely free. 



Pectorals reaching about half-way to the ventrals, 1J 

 in the head. 



Faintly dotted with light brown above; sides and be- 

 low white, probably pink in life; pectoral and dorsal 

 fins dark, their free half nearly black; free half of the' 

 ventrals dusky; other fins plain white. 



Head 6; depth 6; D. 7: A. 30; V. 6; P. 9. 



Seven specimens .10-. 13m. Tabatinga; Jutahy; Tonan- 

 tins; Ic:a. Thayer Expedition. 



250. Cetopsis plumbeus. 



Cetopsis plumbeus Steindachner, Flussfische Sudani, iv, 31, pi. vi, 

 fig. 3, 1882 (Canelos); Boulenger, Proc. Zool. Soc. Lond. March, 

 1887, 276 (Cauelos). 



Habitat; Eastern slopes of Ecuador. 



251. Cetopsis coecutiens. 



Silurus coecutiens Lichtenstein, Wiedem. Zool. Mag. i, part 3, 61, 

 1829 (Brazil); Spix, Gen. et. Spec. Pise. 12, pi. x, fig. 2, 1829 

 (Rivers of equatorial Brazil). 



